Analyzing the Content of a Categorical Variable

Now that we've got a good feel for the kind of information contained in the online retail dataset, we want to dig a little deeper into each of its columns:

import pandas as pd
file_url = 'https://github.com/PacktWorkshops/'\
           'The-Data-Science-Workshop/blob'\
           '/master/Chapter10/dataset/'\
           'Online%20Retail.xlsx?raw=true'
df = pd.read_excel(file_url)

For instance, we would like to know how many different values are contained in each of the variables by calling the nunique() method. This is particularly useful for a categorical variable with a limited number of values, such as Country:

df['Country'].nunique()

You should get the following output:

38

We can see that there are...